Carbon and MXene Dual Confinement and Dense Structural Engineering Toward Construct High Performance Micron‐SiOx Anode for Li‐Ion Batteries

Abstract The intrinsic low conductivity, low tap density, and huge volume expansion during lithium storage severely restrict the practicality of micron‐silicon suboxide (m‐SiO x ). Here, a carbon and MXene dual confinement and dense structural engineering strategy is proposed to construct m‐SiO x composites (m‐SiO x @C/MXene) through in situ carbon coating and electrostatic self‐assembly process. This integrated structural achieves a conductivity of 157 S cm −1 for m‐SiO x @C/MXene, which is 7 and 2 orders of magnitude higher than m‐SiO x (5.3 × 10 −5 S cm −1 ) and m‐SiO x @C (2.9 S cm −1 ), respectively. The tap density of m‐SiO x @C/MXene reaches 1.35 g cm −3 , significantly greater than that of m‐SiO x (0.82 g cm −3 ) and m‐SiO x @C (0.75 g cm −3 ). The 29% volume expansion of m‐SiO x @C/MXene during lithium storage is much lower than the 228% and 162% of m‐SiO x and m‐SiO x @C. The synergistic effect of the above advantages enables m‐SiO x @C/MXene to exhibit excellent rate performance and cycle stability. When assembled into a full cell with the LiFePO 4 (LFP) cathode, it features high capacity retention and energy density of 99.1% and 380 Wh kg −1 after 100 cycles at 0.2 C. This work provides new reference for the stable structural design of m‐SiO x or other materials with huge volume expansion during energy storage.